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Possible breast cancer protective factors

Some things lower the risk of breast cancer such as having a generally healthy lifestyle, including being physically active, and maintaining a healthy body weight. Statistically, if you breastfeed you are at less risk of developing breast cancer, particularly if you have your children when you are younger.

Some research suggests that people with coeliac disease have a lower risk of getting breast cancer.

Drugs to prevent breast cancer

There is research into using drugs to prevent breast cancer. Trials show that the drug tamoxifen can lower breast cancer risk in women at high risk. But there are concerns about side effects for women who are otherwise healthy. We know from other research that women taking aspirin or other non steroid anti inflammatories (such as ibuprofen) have a small reduction in risk of breast cancer. But you shouldn’t start taking these medicines without talking to your GP as they can cause other health problems.

Being physically active

We know from research that physical activity can help to prevent breast cancer. Studies have found a protective effect of about 15 to 20% in women who take half an hour of exercise 5 times a week. So being active may lower your risk of breast cancer by about a fifth. This is probably because physical activity lowers oestrogen and testosterone levels and can delay the start of periods.

Breastfeeding

Statistics show that if you breastfeed you are less at risk of developing breast cancer, particularly if you have your children when you are younger. We don't know exactly why this is. It may be because your ovaries don't produce eggs so often when you are breastfeeding. Or it may be because breastfeeding changes the cells in the breast and may make them more resistant to the changes that lead to cancer.

Diet

Aspirin and anti inflammatory drugs

Research has shown that women regularly using aspirin or other non steroidal anti inflammatory medicines probably have a small reduction in their risk of breast cancer. Remember though that aspirin can irritate the lining of your stomach and cause bleeding. So you should talk to your own GP before starting to take it regularly. You shouldn't take it if you have any history of stomach ulcers.

Medicines to prevent breast cancer

Research is looking into drugs that may prevent breast cancer. Tamoxifen is a drug that has been used to treat breast cancer for more than 35 years. It works by stopping oestrogen from triggering hormone receptors in breast cancer cells. Some women who are at high risk of breast cancer took tamoxifen for 5 years as part of trials to see if it reduced their risk of developing it. In 2014 the IBIS1 trial reported that tamoxifen can lower the risk of breast cancer if you are at high risk. The benefits of tamoxifen in preventing breast cancer seem to last for around 20 years after the treatment ends. The researchers estimate that 1 breast cancer would be prevented for every 22 women who took the drug for 5 years.

Another trial looked at other drugs similar to tamoxifen that are used to treat bone thinning (osteoporosis). These were raloxifene, arzoxifene, and lasofoxifene. These drugs also reduced the number of women who developed breast cancer. The drugs have side effects though and they increase the risk of blood clots and strokes. Tamoxifen also slightly increases the risk of womb cancer.

The National Institute for Health and Care Excellence (NICE) has approved tamoxifen and raloxifene for women at high or moderate risk of developing breast cancer. NICE says that women with an increased risk should talk to their doctor about taking either tamoxifen or raloxifene for 5 years as a possible way of lowering their risk. Both of these drugs have side effects including increasing the risk of developing blood clots and strokes. So, NICE do not recommend them if you have had a blood clot or are at risk of developing one. Tamoxifen also slightly increases the risk of womb cancer.

In December 2013 the results of the IBIS 2 trial were released in the Lancet. The trial compared taking 5 years of the hormone therapy anastrozole with taking a dummy drug (placebo). 4000 women took part in the trial and they all had a high risk of developing breast cancer. Taking anastrozole reduced the risk by more than 50% in these women. Anastrozole caused fewer side effects than tamoxifen. The researchers stated that anastrozole works better in this situation than tamoxifen. They recommend that it should be considered in the future as a treatment option for women at high risk of developing breast cancer.

Coeliac disease

Coeliac disease is a disease of the small bowel. In people with coeliac disease, their body has an immune reaction to gluten, a protein found in rye, wheat and barley. This causes inflammation, which over time can damage the lining of the small bowel. This makes it difficult for the bowel to absorb the nutrients we need from our food. Symptoms of coeliac disease include bloating and discomfort in the tummy (abdomen), diarrhoea, a low red blood cell count (anaemia) and tiredness. People with coeliac disease have to stick to a gluten free diet.

Some research suggests that people with coeliac disease have a lower risk of getting breast cancer. A study looked into why this might be the case. The study reported in 2012. The research team found that women with coeliac disease had some factors that increase and some factors that decrease the risk of breast cancer developing. They suggest that the reduced risk of breast cancer is related to menstrual and reproductive factors. You can read the results of the coeliac disease and breast cancer risk study on our clinical trials database.

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